What is Java Web Start and how is it launched?

The Java Web Start software allows you to download and run Java applications from the web. The Java Web Start software:

Provides an easy, one-click activation of applications

Guarantees that you are always running the latest version of the application

Eliminates complicated installation or upgrade procedures

Getting Java Web Start Software

Java Web Start is included in the Java Runtime Environment (JRE) since release of Java 5.0. This means that when you install Java, you get Java Web Start installed automatically.
The Java Web Start software is launched automatically, when a Java application using Java Web Start technology is downloaded for the first time. The Java Web Start software caches (stores) the entire application locally on your computer. Thus, any subsequent launches are almost instantaneous as all the required resources are already available locally.
Every time you start the application, the Java Web Start software component checks the application's website to see if a new version is available, and if so, automatically downloads and launches it.

Launching an Application Using Java Web Start Software

From a browser

Click on a link from a web page.

From desktop icon

If you use an application frequently, you can create a shortcut on your desktop or in the Start Menu. Java Web Start may ask if you would like to create shortcuts or an entry in the Start Menu. If you reply Yes, all future launches of the application can start without a browser.

From Java Application Cache Viewer

Java Web Start also provides an Application Cache Viewer which you can launch from the Java Control Panel. The Cache viewer enables you to directly launch applications that you have downloaded.

Instructions to launch from Application Cache Viewer

Go to Start > Settings > Control Panel > Double click on the Java icon. The Java Control Panel will start.

Click on the General tab

Click on the View button from the Temporary Internet Files section

Double click on the respective application from the list that you want to launch

From command prompt

You can also launch an application from a command prompt by typing javawsjnlp_url where jnlp_url is a url to the jnlp file of the application.